About the Study

The Sleep Heart Health Study is a multi-center cohort study implemented by the National Heart Lung & Blood Institute to determine the cardiovascular and other consequences of sleep-disordered breathing. It tests whether sleep-related breathing is associated with an increased risk of coronary heart disease, stroke, all cause mortality, and hypertension.

The SHHS1 dataset represents data from the baseline and first follow-up visits, collected on 6441 individuals between 1995 and 1998.

Participants were recruited from nine existing epidemiological studies in which data on cardiovascular risk factors had been collected previously. The “parent” cohorts include:

• The Framingham Offspring Cohort
• The Hagerstown and Minneapolis/St. Paul sites of the Atherosclerosis Risk in Communities (ARIC) study
• The Hagerstown, Sacramento and Pittsburgh sites of the Cardiovascular Health Study (CHS)
• The Strong Heart Study sites in South Dakota, Oklahoma, and Arizona
• Studies of respiratory disease in Tucson and of hypertension in New York

From these parent cohorts, a sample of participants who met the inclusion criteria (age 40 years or older; no history of treatment of sleep apnea; no tracheostomy; no current home oxygen therapy) was invited to participate in the baseline examination of the SHHS, which included an initial polysomnogram (SHHS-1). Several cohorts over-sampled snorers in order to increase the study-wide prevalence of sleep-disordered breathing. In all, 6441 individuals were enrolled between November 1, 1995 and January 31, 1998. During exam cycle 3 (January 2001- June 2003), a second polysomnogram (SHHS-2) was obtained in 3295 of the participants.

Polysomnograms were obtained in an unattended setting, usually in the homes of the participants, by trained and certified technicians. The recording montage consisted of:

• C3/A2 and C4/A1 EEGs, sampled at 125 Hz
• right and left electrooculograms (EOGs), sampled at 50 Hz
• a bipolar submental electromyogram (EMG), sampled at 125 Hz
• thoracic and abdominal excursions (THOR and ABDO), recorded by inductive plethysmography bands and sampled at 10 Hz
• “airflow” detected by a nasal-oral thermocouple (Protec, Woodinville, WA), sampled at 10 Hz
• finger-tip pulse oximetry (Nonin, Minneapolis, MN) sampled at 1 Hz
• ECG from a bipolar lead, sampled at 125 Hz for most SHHS-1 studies and 250 Hz for SHHS-2 studies
• Heart rate (PR) derived from the ECG and sampled at 1 Hz
• body position (using a mercury gauge sensor)
• ambient light (on/off, by a light sensor secured to the recording garment)

Participating Institutions

• Boston University
• Case Western Reserve University
• Johns Hopkins University
• Missouri Breaks Research, Inc.
• New York University Medical Center
• University of Arizona
• University of California at Davis
• University of Minnesota – Clinical and Translational Science Institute
• University of Washington